Load survey recorder for measuring electrical parameters

ABSTRACT

A survey recorder for measuring electrical loads and providing a magnetic tape record of data with time reference signals in format capable of providing computer compatible information. The data recording circuit utilizes a light emitting diode with a phototransistor to determine each quantum measurement by the meter, and a trigger circuit driven by the phototransistor feeds a solid state divider circuit which is programmable to provide various I/O pulse ratio outputs to the data recording head. A power outage circuit detects outages which are greater than a predetermined duration and provides distinctive pulses to a time recording circuit to effect a recognizable format on the magnetic tape which identifies the power outage.

BACKGROUND OF THE INVENTION

The electrical utility field has in recent years increased its use ofrecording devices which are capable of automatically providingcomputer-compatible information relating to the use and operation of theelectrical distribution systems which supply power to the ultimateconsumer. Typically, such recorder devices have application in customerstudy analysis, load survey work, load monitoring, automatic billing,data collecting and the like.

In load survey work, by way of example, the recorder device may be usedto provide a data record which is of assistance to the utility companyin its evaluation of the load conditions for the different types ofcustomers, and further in the evaluation of the rate structures whichare reasonably used for the types of loads involved.

The same recorder device may also be used to record information forbilling purposes, whereby labor costs and possible errors in billing arereduced. In yet another application, such type recorder device may beused tO provide a detailed record of information which permits moreaccurate evaluation of system performance. By way of example, the systemengineers for a utility company may find reason to be concerned aboutthe coincident load values at two or more points in the electricaldistribution system of such utility. In such instances, a recordingdevice may be located at each point of service to record the informationfor each demand interval, and the sum of all loads during a demandinterval can be readily determined by a careful and studied review ofthe recorded information.

In yet other instances, the utility engineers may be required to provideinformation which supports proposed rate schedules, or for justificationof existing rate schedules, and the recorded data provided by therecorder device provides the basis for the establishment of fair andequitable rate assignments. These and other uses for and of recordersurvey devices are well known in the field.

While pulse recorder equipment has been known heretofore for suchpurposes, there is a need for a more flexible and reliable type recorderunit which provides data records of such field information.

It is an object of the invention therefore to provide a device which isso operative, and specifically which has the ability to provide amagnetic tape recording of data relating to the load measured by autility meter along with a time reference in a form which is compatiblefor use with available data processing equipment.

SUMMARY OF THE INVENTION

The survey recorder of the invention basically comprises a two-trackcassette recorder including recorder circuitry having a first sectionresponsive to low voltage data input pulses to record a data track onthe cassette tape, and a second section responsive to timing pulses toprovide a time track recording which identifies predetermined timeintervals in which data recording occurs. NRZ recording format is usedfor the recording of both data and time information, a change inpolarity occurring on the data track with the receipt of each data pulseinput to the first section, and a change in polarity in the time trackoccurring with the input of each timing pulse input to the secondsection.

The data input source in a preferred embodiment comprises a novel pulseinitiator circuit which utilizes a light-emitting diode and aphototransistor with solid state circuitry to detect each rotation of ameter disc. A Schmitt trigger is utilized for level sensing to reduceprobabilities of the recording of false pulses due to irregularity todisc motion. A solid state divider driven by the Schmitt trigger outputprovides an arrangement whereby various pulse ratios may be programmedto the data section of the recorder circuitry.

A power output circuit generates a distinctive signal which is recordedon the time track only when a power outage of greater than twentyseconds duration occurs, whereby switching transients and voltage dipswill not effect an improper indication of power outage.

The novel power outage code as provided by such circuit consists of (a)two one-half amplitude pulses of the same polarity immediately followingone another, (b) the second one-half amplitude pulse of the pairoccurring at the time of transition of the interval timing switch (c)half amplitude measurements which are determined by comparison of therelative amplitude of the incoming pulse to the average amplitude of theprevious five pulses.

The survey recorder thus provides not only a reliable record of customerload and demand data, but additionally provides a reliable indication ofany interruption in the continuity of the data recording.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 and 2, as placed in adjacent relation, set forth a preferredembodiment of the novel survey recorder;

FIG. 1A discloses a calibrated meter disc for use with the surveyrecorder;

FIG. 1B is a showing of the pulse output of the pulse initiator for onerevolution of the meter disc;

FIGS. 3A, 3C set forth representative current flows over data head andtime head; and,

FIGS. 3B, 3D set forth the playback waveforms which occur as a result ofthe current flow of FIGS. 3A, 3C over the data and track heads duringrecording.

SYSTEM DESCRIPTION

With reference to FIGS. 1 and 2, the survey recorder circuit 10 of thepresent disclosure basically comprises a watthour meter M arranged forconnection to a 110 or 220 volt AC source for measuring the power usedby a consumer, a synchronous motor 27 connected to the AC source foroperating the tap drive 20 of a cassette tape recorder unit 14 via geardrive 21, and for also driving a cam 26 in the periodic generation oftiming pulses, a DC power supply 18 connected to the AC source forproviding DC power to the survey recorder circuitry, a pulse initiatorcircuit 12 for providing data pulses representative of the amount ofpower measured by the meter M, and a recorder circuit 16 including atime record circuit 15 and a data record circuit 17 for providing dataand time signals to the two heads of the data and time record heads DH,TH of the recorder 14, a logic control circuit 127 for the time recordcircuit 15 and a power outage circuit 125.

DC Power Supply Source 18

DC power supply circuit 18 which is connected over conductors 22, 24 tothe 120 volt (or 240 volt) AC source is operative to provide a 12.5 voltDC output over conductors 38 and 49 to the pulse initiator circuit 12and the recorder circuit 16 respectively.

More specifically, conductors 22, 24 conduct the AC source to theprimary winding 29P of a transformer 29 which provides a 12.5 volt ACoutput across its secondary winding 29S. Surge protector 28 is connectedacross the primary winding 29P, and capacitor 30 is connected oversecondary winding 29S for the purpose of attenuating and filtering highfrequency noises from the output of the transformer 29. The 12.5 volt DCoutput of the transformer 29 is rectified by full wave rectifier 32, theoutput of which in turn is filtered by capacitor 34, and applied acrossload resistor 36 to the DC supply conductor 38 for the pulse initiator12 and over DC supply conductor 49 for the recorder circuit 16.

Sync Motor 27

Synchronous motor 27 has its input conductors 23, 25 connected directlyacross the AC source, and is continuously operable whenever AC power isinput to the meter M. In one embodiment shown in the copendingapplication of Murray C. Carney and David G. Hart, filed as of even datefor Load Survey Recorder and assigned to the assignee of this invention,the sync motor 27 via gear train 21 drives the tape drive 20 of acassette recorder to advance the tape T past the time record head TH andthe data record head DH of recorder 14 at approximately 1/900 ips. Geartrain 21 simultaneously drives a single lobe cam 26 (FIG. 2) whichoperates an associated microswitch SW1 to provide a timing pulse every15 minutes of operation of the synchronous motor 22. As will be shown,such pulses in turn enable the control circuit 127 to control the timerecord circuit 15 to record a discrete timing signal on the cassettetape to indicate the times of occurrence of the 15 minute intervals, andfurther to indicate power outages which exceed 20 seconds in duration.

Pulse Initiator Circuit

Pulse initiator circuit 12 is operative with meter disc 10 of meter M toprovide digital pulses to the recorder circuit 16, each of whichrepresents a predetermined number of rotations of the meter disc 10 ofthe watt-hour meter M. As is known in the art, a conventional watthourmeter, such as the type commercially available from Sangamo ElectricCompany, Springfield, Illinois, as a J4 meter, normally locates a darkzone 11 (see FIG. 1a) on the underside of the meter for use in metercalibration during meter assembly in the plant. In the presentembodiment, pulse initiator circuit 12 includes a light-emitting diode40 (FIG. 1) which is mounted to direct its light output toward theunderside of meter disc 10 for reflection back to a phototransistor 41.In each revolution of the meter disc 10, as the black zone 11 is movedinto the area of light engagement with the under surface of the disc 10,the reflected light is reduced significantly to the phototransistor 41.

In operation, the light output of the light-emitting diode 40 which isdirected toward the meter disc 10 is normally reflected back to thephototransistor 41 to enable the phototransistor 41 to provide a firstoutput signal. As the dark zone 11 on the disc 10 moves into the area oflight output of diode 40, the absence of reflected light to thephototransistor 41 will cause the phototransistor 41 to provide a secondor different signal output. As will be shown, the changing signaloutputs of phototransistor 41 are used to generate data pulses whichrepresent a count of the meter disc revolution for recording purposes.

More specifically, a light-emitting diode 40 is connected over conductor38 to the 12.5 volt output of DC supply source 18, and via transistor 42and resistor 44 to ground. Light emitting diode 40 therefore provides alight output whenever power is present at the 120 volt AC (or 240 volt)input. Transistor 42 connected in series with diode 40 operates in knownmanner to provide a constant current for the diode 40. Resistor 43 isconnected to conductor 38 and provides current to the 5.1 volt Zener 48and diode 46 which forms a constant voltage supply over conductors 47and 50 to the components of the pulse initiator circuit 12. Diode 46 isconnected in series with Zener diode 48 across the base-emitter circuitof transistor 42 in a temperature-compensating mode. With such anarrangement the normally negative temperature coefficient of the base toemitter junction of transistor 42 is compensated by the nagativetemperature coefficient of diode 46.

The constant voltage on conductor 50 is connected to phototransistor 41and a Schmitt trigger circuit 64, and the constant voltage on conductor47 is connected over a buffer circuit 52 comprised of diode 54 andcapacitor 56 and conductor 58 to integrated divider circuit 84. Buffercircuit 52 minimizes momentary flickers which may occur in the currentsupplied over conductor 58 to the programmable divider circuit 84, andthereby the possibility of false counts by the divider circuit.

Phototransistor 41 and diode 40 may be of the type commerciallyavailable as Fairchild FPA 103. Phototransistor 41 is located, as shown,to have its base element respond to the output light of diode 40 asreflected from the underside of meter disc 10. Phototransistor 41conducts during the period that the light output of the diode 40 isreflected by the meter disc 10 to the base element of phototransistor41, and is less conductive during the period that the dark zone reducesreflection of such light. The collector current output of transistor 41is fed over resistor 62 to the input circuit for trigger circuit 64. Thetrigger circuit 63 includes a first transistor 66 having its emitterelement connected over common emitter resistor 72 to constant voltageconductor 50, its base element connected over resistor 62 to the outputof phototransistor 41, and its collector element connected over resistor68 to ground. The collector of transistor 66 is also connected overresistor 70 to the base element of the second transistor 76 in thetrigger circuit 64. Transistor 76 has its base element further connectedover bias resistor 74 to the constant voltage supply conductor 50; itsemitter element connected common with the emitter of transistor 66 overresistor 72 to the constant voltage conductor 50; and its collectorconnected over resistor 78 to ground, and also to the base of drivetransistor 80.

Transistor 80 has its emitter element connected to ground, and itscollector connected over resistor 82 to constant voltage conductor 58,and to input pin 1 of the divider circuit 84, which may be of the typecommercially available from RCA as CD4024AE.

The output of divider circuit 84 may be taken from terminals 12, 11, 9,or 6 which respectively causes a change in the logic output after theinput of 2, 4, 8, or 16 pulses to terminal 1 by the trigger circuit 64,whereby different pulse output rates may be selectively programmed byconnecting the resistor 86 to correspondingly different ones of theoutputs of divider 84. The selected output of divider 84 is fed overresistor 86 to amplifier transistor 88, and thence over output conductor90 to the data track circuit 17 in recorder circuit 16.

Operation of Pulse Initiator Circuit 12

Meter disc 10 rotates as shown at a speed which is proportional to theamount of energy being used by the load. As noted above, the lightoutput of light-emitting diode 40 is normally reflected by the undersideof the meter disc 10 to the base of the phototransistor 41. Once in eachsuch rotation of the meter disc 10, light is reflected from thelight-emitting diode 40 to the phototransistor 41 to change the signaloutput of phototransistor 41 to trigger circuit 64.

During the period that the light output of light-emitting diode 40 isreflected to phototransistor 41 the collector voltage of phototransistor41 is low, and such signal as applied to the base element of transistor66 in the trigger circuit 64 drives transistor 66 into saturation. Thecollector voltage of transistor 66 in turn goes more positive, and theresultant positive-going signal at the base of transistor 76 causestransistor 76 to turn off. With transistor 76 turned off, the voltage ofthe collector of transistor 76 decreases, and the driver amplifier oftransistor 80 likewise is turned off. With drive transistor 80 off, thevoltage at the collector of transistor 80 is high (i.e., a logic 1signal) and a logic 1 signal is input to the divider 84 (see logic 1,interval WX--FIG. 1B).

Assuming now that the meter disc 10 rotates to bring the dark zone 11 onthe meter disc 10 into position to reduce the reflection of the lightoutput from diode 40 to phototransistor 41, the transistor 41 turns offto provide a positive-going signal to the first transistor 66 of thetrigger circuit 64. Transistor 66 turns off to thereby cause transistor76 to turn on. The signal output to the base of transistor 80 is nowpositive-going and transistor 80 turns on to cause the voltage at itscollector to drop, and provide a logic zero output to the input fordivider circuit 84. Divider circuit 84 responds to the leading edge ofeach negative-going pulse by adding a count. The divider however doesnot respond (i.e., add a count) with the occurrence of eachpositive-going trailing edge which occurs as the dark zone 11 on themeter disc 10 moves out of the path of the light output of diode 40. Atsuch time, the light output of diode 40 is once more reflected totransistor 41, the phototransistor 41 turns on, transistor 66 turns on,transistor 76 turns off, and transistor 80 turns off to provide theleading edge of a logic 1 pulse to divider circuit 84 (Y, FIG. 1B). Asnoted above, the divider circuit 84 does not respond to such signal. Thetrigger circuit 64 provides a logic 1 output to divider circuit 84 untilthe next time phototransistor 41 turns off by reason of the reduction ofthe reflected light by the dark zone 11 on meter disc 10.

As noted, divider circuit 84 adds a count for each negative-going pulseoutput from the trigger circuit 64. After a predetermined number of suchcounts are recorded, divider circuit 84 changes the signal output overcircuits C1-C4. In the disclosed embodiment, divider 84 is programmableby suitable positioning of resistor 86 to provide a change in the pulseoutput for each 1, 2, 4 or 8 revolutions of meter disc 10. Thus, if thepulse output of divider circuit 84 over conductor C3 is a logic 0, thedivider circuit will change such output to a logic 1 as the fourthnegative going pulse is input to the divider circuit 84 from the triggercircuit 64.

The pulse output of divider circuit 84 is amplified by amplifier 88 andfed over a cable 90 to the data record circuit 17 in the recordercircuit 16.

A greater number of pulse ratios may be provided in conjunction with thesolid state divider circuit by painting the disc with an additionalnumber of dark zones. Thus, for example, 16 dark zones such asillustrated zone 11 may be located on the disc, whereby each of theseven stages of the divider circuit 84 may be used to provide pulseratios of R/P=4, 2, 1, 0.5, 0.25, 0.125 and 0.0625.

An electronic multiplying circuit may also be used in conjunction with adifferent number of dark zones on the disc and the electronic dividercircuit 84 to in effect provide any practical fractional pulse ratiodesired. In such arrangement the output of the trigger circuit 64detecting the multiple dark zones is fed to the divider circuit 84 asbefore and the output of the divider circuit is fed to a programmablemultiplier circuit (not shown). The output of the multiplier circuit isin turn fed to transistor 88. The divider and multiplier circuit arepreferably programmable so that integer division and multiplication fromabout 1 to 10 for various pulse ratios can be obtained. The unusualflexibility provided by such circuitry will be readily apparent to thoseskilled in the art.

The duration of the successive pulses output by pulse initiator circuit12 (FIG. 1B) will vary in direct relation to the speed of rotation ofthe meter disc 10, which is, in turn, determined by the rate of powerconsumption by the load being measured.

Recorder Circuit 16

The recorder circuit 16 includes a data recorder head (DH) 94 forrecording the data inpulses received over conductor 90 from the pulseinitiator circuit on one track of the magnetic tape T, and a time recordhead (TH) 98 which provides a record of each 15 minute interval ofoperation of the watthour meter M.

Both date and time information are recorded in the NRZ (non-return tozero) format, a continuous direct current flow being provided over therecording head RH, TH whenever AC power is present on the power circuitbeing monitored. The direction of current flow over head 94 in the datarecord circuit 17, and therefore the polarity of the tape magnetizationis controlled by the signals output over conductor 90 by the pulseinitiator circuit 12. That is, with the input of each pulse overconductor 90 to the data record circuit 17 by pulse initiator circuit12, the direction of current over data record head 94 is reversed tochange the polarity of tape magnetization.

A chart (FIG. 3a) shows the current flow over the data head DH with thereceipt of a representative set of pulses from pulse initiator circuit12. It will be seen from FIG. 3a that the polarity of the currentchanges as each successive pulse is input from the pulse initiatorcircuit 12, the duration of each polarity pulse varying directly withthe amount of power consumed by the user. That is, the rate at which thepulses output over conductor 90 by the pulse initiator circuit 12 varydirectly with the amount of power being measured by the watthour meterM, and since the tape is driven at a fixed rate, the duration of thepolarity pulse recorded will vary directly with the duration of thepulse input over conductor 90 and the amount of power being used.

Data Record Circuit

Data record circuit 17 basically includes a recording head 94 which hasone end connected over resistance 102 to 12.5 DC volts on conductor 49,and its other end connected over resistors 114 and 104 to the 12.5 voltsupply conductor 49. Transistor 100, which is operative to determine thedirection of flow of current over the data recording head 94, includes acollector connected over resistor 102 to the 12.5 DC supply conductor49, an emitter connected to ground, and a base connected over diodes106, resistor 108 and resistor 104 to the 12.5 volt DC conductor 49, anda forward bias circuit including parallel resistor 110 and capacitor 112connected across the base-emitter circuit of transistor 100 to ground.The base of transistor 100 is also connected over diodes 106, resistor108 to the output conductor 90 of the pulse initiator circuit 12.Resistors 104, 108 and diodes 106 provide a 2-volt bias level whichminimizes operation of transistor 100 in response to spurious noiseswhich might appear on conductor 90 of the pulse initiator circuit 12. RCfilter 110, 112 is a noise suppression circuit for further assisting inminimization of improper operation of transistor 100.

Data Recording

As noted above, data is recorded on the data track in an NRZ format, thedata track circuit 17 being operative to effect reversal of thedirection of current flow over data head 94 with each change in thepolarity of the signal output over conductor 90 from the pulse initiatorcircuit 12.

It will be recalled that with each four revolutions of the meter disc,the signal output from the pulse initiator circuit 12 changes. Thus, ifthe signal on conductor 90 was a logic 0, the output signal on conductor90 changes to logic 1 (and vice versa) with each four completerevolutions of the meter disc 10.

Assuming initially that the signal on conductor 90 is a logic 1 (seeFIG. 1b) such signal as applied over resistor 108, diodes 106 to thebase-emitter circuit of transistor 100 causes transistor 100 to turn on,and current flows over a path which extends from +12.5 volts DC overresistor 104, 114 and data head 94 (from minus to plus) and transistor100 to ground. With such current flow over data head 94, a negativepolarity signal is applied to the magnetic tape (pulse interval A inFIG. 3a).

Control transistor 100 remains in such condition for the period thatfour complete revolutions of meter disc 10 occur. At such time, thesignal output from pulse initiator circuit 12 over conductor 90 changesto a logic 0, and the direction of current flow over data head 94 isreversed to provide a positive polarity signal to the magnetic tape(pulse interval B, FIG. 3b). That is, with the application of logic 0over conductor 90 and resistor 108 and diodes 106 to the base emittercircuit of transistor 100, transistor 100 is biased off, and currentflows over a path which extends from +12.5 volts DC over resistor 102,data head 94 (from plus to minus), resistor 114 through transistor 88 ofpulse initiator circuit 12 to ground.

The plus to minus current flow continues during the period that fourmore revolutions of meter disc 10 occur at which time divider circuit 84changes the state of its output to logic 0 to cause transistor 88 to beturned off, and thereby provide a logic 1 output over conductor 90(pulse interval C--FIG. 3a) to turn transistor 100 on and cause thecurrent to once more flow over data record head 94 from minus to plus.

By integrating the leading edge of each pulse on the data track, dataplayback signals, such as shown in FIG. 3b are provided, which signalsgive an accurate representation of the number of revolutions of meterdisc 14.

As will now be shown, time information is recorded on a second track oftape T to provide a time reference for the recorded data, whereby theamount of power used in successive periods of time can be accuratelydetermined from the playback signals.

Time Track Circuit 15

Synchronous motor 27 (FIG. 1) via gear train 21 drives a cam 26 tooperate switch Sw1 to move switch arm 132 to open contacts B and closecontacts A for approximately 30 seconds to initiate each 15 minuteinterval (see pulse interval F--FIG. 3c). As will be shown, with switchSW1 in its normal position (i.e., as shown in FIG. 2 switch arm 132connects ground to contacts B), current flows over timer head 98 fromright to left to provide a negative polarity signal for the tape timetrack. During the 30 second interval in which switch arm 132 closescontacts A the current flow over head 98 is from plus to minus toprovide a positive polarity signal on the time track (see pulse intervalF--FIG. 3c). At the end of the 30 second interval, cam 26 causes theswitch arm 132 to once more connect ground to contacts B, and therebyreverse the direction of flow of the current over time period head 98 toprovide a negative polarity signal to the time track for the next 141/2minutes (pulse interval E--FIG. 3c).

Time recording circuit 15 also includes a power outage circuit 125 whichwill not provide a record of power outages which are less than 20seconds in duration, and which reestablishes current flow in the timerecord head 98 in the same direction as existed prior to theinterruption. Power outage circuit 125 is further operative to recognizepower interruptions which last more than 40 seconds, and when powerreturns to provide a distinctive marking signal on the track bypreventing restoration of current flow over the time track head 98.During such period zero current level is applied to time head track 98and a half amplitude pulse results (interval KL--FIG. 3c). As the switchSW1 operates to provide a pulse, as noted above, which initiates the endof 15 minutes of meter operation, the power outage circuit 125 operatesto reestablish current flow through the time record head TH which byreason of the previous zero current level (interval KL--FIG. 3c) resultsin a second half amplitude pulse on the tape (interval LMN--FIG. 3c). Atthe end of the 30 second period MN, the timing pulse causes current flowto be reversed to provide a negative polarity pulse (interval NOP--FIG.3c) and the system operates to record time pulses in the normal manneruntil a further power outage occurs.

The format recorded on the tape where a power outage occurs thuscomprises two half amplitude pulses with a location and polarity whichviolate the requirements of a legitimate time pulse to thereby providemarking of power outages in a new and unusual pattern. In the playbackformat (FIG. 3d), the power outage code may be recognized by (a) thedetection of two 1/2 amplitude pulses of the same polarity immediatelyfollowing one another, (b) the second 1/2 amplitude pulse occurring atthe time of the microswitch operation, (c) and for reliability comparingthe relative amplitude of the incoming pulse to the average amplitude ofthe previous five pulses. The operation of the time record circuit inthe provision of such tape record is now set forth.

Time track circuit 15 basically comprises first and second currentcontrol transistors 117, 118 which are enabled in their operation by acontrol circuit 127, a power outage circuit 125, and switch SW1 in amanner to be described. Whenever control transistor 117 is caused toconduct, a path is established for the time record head 98 which extendsfrom +12.5 volts DC on supply conductor 49 over diode 116, transistor117 and in parallel over resistor 121 to ground, and over time recordhead 98 from plus to minus and over resistors 119, 120 to ground.Whenever control transistor 118 conducts, a current path is establishedfor the time record head 98 which extends from +12.5 volts DC on supplyconductor 49 over diode 116, transistor 118 and a parallel circuitincluding resistor 120 in one leg, and resistor 119, head 98 from minusto plus and resistor 121 to ground in the second leg.

To summarize, with control transistor 117 enabled, a positive polaritysignal is recorded on the time track, and with control transistor 118enabled, a negative polarity signal is recorded on the time track. Ifneither of the transistors 117, 118 is conducting, zero current issupplied to the time track.

Power Outage Circuit

The stage of transistors 117, 118 is controlled by control circuit 127,switch SW1 and power outage circuit 125. Power outage circuit 125includes a timing capacitor 130 which is connected over resistor 131 anddiode 115 to the 12.5 volts DC on conductor 49. A discharge resistor 122is connected between the positive plate of capacitor 130 and ground, andthe junction of resistors 131, 122 and capacitor 130 is connected overresistor 123 to terminal 5 of a latch circuit 124 which includes a pairof NAND gates 126, 128 connected in a latching configuration wheneveroutput terminal 4 of gate 126 is connected to input terminal 2 of gate128 and the output terminal 3 of gate 128 is connected to the inputterminal 6 of gate 126. A power input terminal 14 on gate 126 in latchcircuit 124 is also connected with capacitor 137 over diode 129 to the12.5 volt DC on conductor 49.

Capacitor 137 furnishes DC power to the latch circuit 124 allowing it tooperate for at least the first 40 seconds of loss of power on sourceconductor 49.

With reference to latch circuit 124, input terminal 1 on the second gate128 of latch 124 is connected (a) over resistor 138 to 11.8 volt DC, (b)over capacitor 140 and diode 144 to contact B of switch SW1, and furtherto input terminal 12 of NAND gate 134, (c) over capacitor 146, diode 150to contacts A of switch SW1 and further to input terminal 8 of NAND gate136. The junction of capacitor 140 and diode 144 is connected overresistor 142 to 11.8 volts DC, and the junction of capacitor 146 anddiode 150 is connected over resistor 148 to 11.8 volts DC.

The signal output of latch circuit 124 is connected to an input terminalof NAND gate 134 and NAND gate 136, the outputs of which directlycontrol the state of transistors 117, 118.

Input terminal 12 on gate 134 is connected via diode 154 to the outputof gate 136, and input terminal 8 of gate 136 is connected via diode 153to the output of gate 134 to assist in maintaiing each gate 134, 136 ina known state while switch SW1 is making its transition from A to B orvice versa.

The output of gate 134 is connected via resistor 156 to the base elementof transistor 117, a logic 0 output from gate 134 effecting conductionof transistor 117, and a logic 1 output effecting turnoff of transistor117. In like manner, the output of gate 136 is connected via resistor160 to the base element of transistor 118, the logic 1 output from gate136, effecting turnoff of control transistor 118 and the logic 0 outputeffecting conduction of control transistor 118.

Operation of Time Record Circuit 15

As the circuitry is first connected to the 120 or 240 volt power source(or at such time as the power has been off for a period of over 40seconds), transistors 117 and 118 will be turned off by reason of thereset condition of latch circuit 124 as will be shown.

As the 120 volt (or 240 volt) AC power is restored, capacitor 130 willbegin to change over the path which extends from conductor 49 via diode115, resistor 131 and capacitor 130 to ground. While capacitor 130 ischarging, the voltage signal at terminal 5 of gate 126 will besignificantly less than the 11.8 volts DC, and will in effect comprise alogic 0 signal input to terminal 5. Power supplied on terminal 14 ofgate 126 via diode 129 will be 11.8 volts DC.

Since gate 126 is a NAND gate, with logic 0 at terminal 5 the outputterminal 4 will be a logic 1 and terminal 2 of gate 128 will also be alogic 1, (i.e., with any input at logic 0, a NAND gate outputs a logic 1and with both inputs at logic 1 a NAND outputs a logic 0).

Since 11.8 volts DC (logic 1) is also applied over resistor 138 toterminal 1 of NAND gate 128, both input terminals 1 and 2 are a logic 1and output terminal 3 of gate 128 will be at logic 0. The logic 0 outputof gate 128 is connected to (a) terminal 6 of gate 126, thus providingfeedback to the latch circuit 124 (b) terminal 13 of gate 134, and (c)terminal 9 of gate 136.

With input terminal 13 at logic 0, the output of NAND gate 134 will belogic 1 and transistor 117 will be turned off. In like manner with inputterminal 9 of NAND gate 136 at logic 0, the output of gate 136 will belogic 1 and transistor 118 will be turned off. With transistors 117 and118 turned off, there will be no current flowing through the timerecording head 98. Such circuit condition (i.e., zero level current flowover time record head 98) occurs whenever the AC power is first appliedto the system, or whenever the power is restored after more than 40seconds of a power outage, and such circuit condition continues toprevail until the next operation of switch SW1 by cam 26 and synchronousmotor 27.

During such period after startup and prior to operation of switch SW1,the logic 0 output from gate 128 to terminal 6 of gate 126 holds latchcircuit 124 stable in such condition (i.e., logic 0 output) even thoughcapacitor 130 meanwhile charges to 11.8 volts DC to change the signal onterminal 5 of gate 126 from logic 0 to logic 1 (i.e., with logic 0 onterminal 6, the gate 126 will provide a logic 1 output).

Operation of Switch SW1

As synchronous motor 27 drives cam 26 to the camming position, a new 15minute timing interval is initiated (and assuming the switch SW1 is inthe illustrated contact position B) switch arm 132 is moved from contactB to contact A by cam 26 to provide a timing pulse to control circuit127. That is, as switch arm 132 operates to close contacts A, ground isconnected to the junction of diode 150 and terminal 8 on gate 134. Withthe connection of ground to contact A, such ground instantaneouslyappears via diode 150 and capacitor 146 at terminal 1 on gate 128 oflatch circuit 124. With logic 0 on terminal 1 of gate 128, terminal 3will output logic 1 to (a) terminal 13 of gate 134, (b) terminal 9 ofgate 136 and (c) terminal 6 of latch gate 126.

Since terminal 5 of latch gate 126 was at logic 1, as terminal 6 of gate126 goes to logic 1, the output terminal 4 of gate 126 outputs logic 0to terminal 2 of gate 128 to maintain a logic 1 output from gate 128.

Simultaneous with connection of ground to contacts A, a charging circuitis completed for capacitor 146 which extends from +11.8 volts Dc overresistor 138, capacitor 146, diode 150, contacts A, and switch blade 132to ground. Capacitor 146 starts charging towards +11.8 volts at a ratedetermined by the value of resistor 138 and capacitor 146. After apredetermined time determined by the RC characteristics of such circuit,capacitor 146 is fully charged and logic 1 appears at terminal 1 of gate128. However, the state of such gate does not change since logic 0, asnoted above, is input to terminal 2 by gate 126 of latch circuit 124(and continues to be until such time as a power outage of greater than40 seconds occurs).

Returning now to control gates 134, 136, as logic 1 is output by latchcircuit 124 to terminals 13 and 9 of gates 134, 136, transistor 117 isturned on and transistor 118 is held off. That is, switch blade 132 atthis time has connected ground (logic 0) over contact A to terminal 8 ofNAND gate 136, and the output of gate 136 remains at logic 1, wherebytransistor 118 remains in the off position.

However, the switch arm 132 in engagement with contact A, ground isremoved from contact B, and a logic 1 signal is applied from the +11.8volt DC source over resistor 142, and diode 144 to terminal 12 of gate134. With logic 1 input to terminal 12, logic 0 is output from gate 134over resistor 156 to the base of transistor 117 to turn on transistor117.

As transistor 117 conducts, current flows from the 12.5 volts DC sourceconductor 49 over diode 116, transistor 117, and a parallel circuithaving a first leg including resistor 121 to ground, and a second legincluding resistor 119, time record head 98 from + to - and resistor 120to ground to provide a positive polarity polarity pulse on the tape.With reference to the time track head current curve shown in FIG. 3c,such current flow is represented by the initial portion F of thewaveforms shown thereat.

As described above, switch blade 132 is controlled to connect ground tocontact A for a period of approximately 30 seconds, and during each suchperiod the current flow over head 98 results in the recording of thefirst time pulse shown in the time track head current curve of FIG. 3c(pulse interval F).

As the timing interval of approximately 30 seconds is completed, thesynchronous motor rotates cam 26 to move switch arm 132 from contact Aand into engagement with contact B.

With reference first to latch circuit 124, the reconnection of ground tocontact B by switch arm 132 results in an instantaneous logic 0 signalover capacitor 140 which appears at terminal 1 of gate 128. However,since the latch circuit is outputting logic 1 at the time by reason ofthe logic 0 on terminal 2, there will be no change in the logic 1 outputof latch circuit 124 to terminal 13 of gate 134 and terminal 9 of gate136.

With connection of ground over contacts B, logic 0 (ground) is alsoapplied to terminal 12 of gate 134 (logic 1 is being applied to terminal13 by latch circuit 124), and gate 134 will provide a logic 1 outputover resistor 156 to the base of transistor 117 to turn off transistor117, and thereby terminate the current flow from positive to negativeover time track head 98.

Switch arm 132 in its engagement with contact B also completes acharging circuit for capacitor 140, which extends from +11.8 volts DCover resistor 138, capacitor 140 and diode 144, contacts B and switcharm 132 to ground. As capacitor 140 charges in the direction of +11.8volts, the signal applied to terminal 1 of gate 128 changes to logic 1;however, latch circuit 124 continues to output logic 1 by reason of thelogic 0 input to terminal 2 of gate 128 by gate 126.

Moreover, with the removal of ground by switch arm 132 from contacts A,a logic 1 signal is applied from the +11.8 volts source over resistor148, diode 150 to terminal 8 of gate 136. With logic 1 input to bothterminals 8, 9 of gate 136, the output of gate 136 changes to logic 0which as applied over resistor 160 to the base of transistor 118, causestransistor 118 to conduct. A transistor 118 conducts, a current path iscompleted from +12.5 volts DC over diode 116, transistor 118, and timetrack head 98 (minus to plus) and a parallel circuit including a firstleg comprised of resistor 119 and resistor 121 to ground, and a secondleg including resistor 120 to ground.

The flow of current in such direction over time track head 98 results ina negative polarity pulse as shown in FIG. 3c for a period ofapproximately 141/2 minutes, and at such time cam 26 operates switch arm132 to cause ground to be connected to contacts A and provide a furtherpositive pulse on the time track which initiates the start of a second15 minute interval.

Such operation continues until such time as the tape on the cassette isexhausted, which, in the embodiment shown in the copending application,results in approximately 35 days of data accumulation.

Power Outage

As noted above, a novel power outage circuit provides a recordedindication of power interruptions which are in excess of 40 seconds.Power interruptions lasting more than 40 seconds nominally will berecognized as a true power outage condition and when the power returns,the power outage circuit prevents current flow over the time track head.At the time of generation of the next timing signal, the power outagecircuit is reactivated and current through the record head isreestablished.

a. Power Interruption of Less Than 20 Seconds

Assuming that during normal operation of the device a power outage ofless than 20 seconds occurs, capacitor 137 in the time record circuit 15begins to discharge over latch circuit 124 and resistors 123 and 122 toground. The tine constant of the RC circuit including capacitor 137,latch 124 and resistor 123, 133 is in the order of 40 seconds.Accordingly, latch circuit 124 will remain latched, and the controltransistors 117, 118 do not change state. There is therefore no poweroutage signal recorded on the time track to indicate the occurrence ofsuch momentary condition.

b. Power Outage of Over 20 Seconds

Assuming now that a power outage occurs for a period of greater than 20seconds, capacitor 130 will discharge completely, and since a poweroutage has occurred, there will be no power to the circuit elementsincluding time head 98. The circuit remains in such condition untilpower is once more reapplied. At such time, the power circuit 125operates as initially described. Briefly, logic 0 on terminal 5 of gate126 results in a logic 1 output from gate 126 to terminal 2 of gate 128.Gate 128 outputs logic 0, and latch circuit 124 is latched to continueto output logic 0 even though the signal input to terminal 5 of gate 126later changes to logic 1 as capacitor 130 charges to its full capacity.

With logic 0 output by gate 128 to terminals 13 and 9 of gates 134, 136respectively, the output of gates 134 and 136 are at logic 1 andtransistors 117, 118 are turned off to interrupt the current flow overthe time track head 98 until switch arm 132 is later operated by cam 26to start a further timing interval.

With reference to FIG. 3c, the legend "Power Off" indicates the mannerin which the signal recorded on the tape is interrupted as a poweroutage occurs, and the manner in which the signal level on the tape goesto zero to provide a first half pulse as power is returned (i.e.,neither negative or positive polarity current flows during the periodimmediately following startup, since transistors 117 and 118 aremaintained off until such time as the 15 minute interval switch SW1 isonce more operated).

Assuming the switch was in the illustrated position with contact Bclosed at the time of the power outage, with the later closure ofcontact A by cam 26, the logic 0 signal via capacitor 146 to terminal 1of gate 128 causes latch circuit 124 to output a logic 1 to terminals 9and 13 of gates 134 and 136. As switch arm 132 closes contact A, gate136 holds transistor 118 off, and gate 134 turns transistor 117 on tocause the current to flow over head 98 from positive to negative whilethe contact A is maintained closed, as shown at LMN in FIG. 3c, tothereby provide a second half amplitude pulse. After approximately 30seconds of meter operation, switch arm 137 moves from contact A andengages contact B, and transistor 118 is turned on and transistor 117 isturned off to effect current flow over head 98 from negative to positiveas shown at NOP in FIG. 3a.

At a time determined by the nature of the useage of this equipment thecassette tape is removed from the recorder and played back over tapeprocessing equipment having a conventional playback head for the purposeof retrieving the recorded information. Assuming the information shownin FIGS. 3a and 3c has been recorded on the tape, the playback signalprovided will be as shown in FIGS. 3b and 3d. It will be seen that apower outage is readily recognized from the characteristics of theplayback signal.

After such information has been retrieved, the tape is subjected to anA.C. erasure to return the tape to a zero bias condition in preparationfor reuse. As a precaution all tapes are A.C. erased before forwardingto the user.

We claim:
 1. In a survey recorder for recording data and timeinformation derived from an associated meter device, a pulse generatorcircuit for providing data pulses, each of which pulses represents acount derived from said associated meter device, timer means operativeto provide time reference signals which represent predeterminedintervals of time of operation of said meter device, recorder meansincluding a data record circuit having a first recorder head winding forrecording the data pulses provided by said pulse generator circuit on amagnetic tape, and a time record circuit having a second record headwinding for recording time reference pulses on said magnetic tape as areference for said data pulses, and a control circuit for said timerecord circuit including power outage means for detecting a powerinterruption to said meter device which is longer than a predeterminedtime duration, and logic means connected to said power outage means andsaid timer means for controlling said time record circuit and saidsecond record head winding to record a discrete pulse format on saidmagnetic tape which identifies the power interruption.
 2. A surveyrecorder as set forth in claim 1 in which said discrete pulse formatprovided by said control circuit comprises at least a first halfamplitude pulse and a second half amplitude pulse recorded in sequenceon said tape, at least one of which occurs simultaneous with one of saidtime reference signals output from said timer means.
 3. A surveyrecorder as set forth in claim 1 in which said time record circuitcomprises a first switching device connected between a source ofpotential and one side of said second record head winding, and a secondswitching device connected between a source of potential and the otherside of said second record head, and in which said logic means includesa first and a second logic gate for controlling enablement and cutoff ofsaid first and second switches respectively, each of said switchingdevices being operative as enabled to provide current flow over saidsecond record head winding in opposite directions, whereby pulses ofcorrespondingly opposite polarities are recorded on said magnetic tapeas said switching devices are operated.
 4. A survey recorder as setforth in claim 1 in which said logic means includes logic gate meansconnected to said timer means for providing signals to control said timerecord circuit to at times provide current over said second record headwinding in a first direction, and to at other times control current flowover said second record head winding in an opposite direction, a latchcircuit operative to a first state in response to application of powerto said meter after a give period of power outage, said latch circuit insaid first state providing output signals to said gate means to controlsaid time record circuit to maintain zero level current to said secondrecord head winding from the time of said application of power to saidmeter device until a further time reference signal is provided to saidcontrol circuit by said timer means.
 5. A survey recorder as set forthin claim 4 which includes further means for operating said latch circuitto a second state in response to said further time reference signal fromsaid timer means, said latch means providing a signal output in saidsecond state which conditions said gate means to control said timerecord circuit to reverse the direction of current flow in response toreceipt there-after of each time reference signal from said timer means.6. A survey recorder as set forth in claim 1 in which said power outagemeans comprises a capacitor which prevents a change in the state of saidtime record circuit in response to power outages of less than apredetermined period.
 7. A survey recorder as set forth in claim 1 inwhich said control circuitry includes a latch circuit for providingcontrol signals to said time record circuit, and capacitor means formaintaining said latch circuit operative to output said control signalsfor a predetermined period after interruption of said power to therebyprevent operation of the time record circuit in response to momentaryoutage.
 8. A survey recorder as set forth in claim 1 in which said logicmeans include a first and second gate for controlling operation of saidtime record circuit and timer means comprise a switch for connecting asignal alternately to a first input on said first and second gates, andin which said control circuit includes a latch circuit, an RC circuitconnected to one input terminal for said latch circuit to providesignals indicating the presence and loss of power, a first markingcircuit comprising a first capacitor and first diode connected between asecond input of said first gate and a second input for said latchcircuit, and resistance means connected between a potential source andthe junction of said first capacitor and said first diode, a secondmarking circuit comprising a second capacitor and a second diodeconnected between a second input of said second gate and said secondinput of said latch circuit, and resistance means connected betweenpotential source and the junction of said second capacitor and saidsecond diode, and resistance means for connecting a potential to thejunction of said first and second capacitor and said second input forsaid latch circuit, and in which said time record circuit comprises afirst and a second transistor, and means for connecting the output ofsaid first gate to control operation of said first transistor and meansfor connecting the output of said second gate to control operation ofsaid second transistor.
 9. A survey recorder as set forth in claim 1 inwhich said pulse generator circuit includes first means for providing asignal output to indicate each count output by said meter, a triggercircuit connected to the output of said first means operative toalternate states in response to receipt of each successive signal fromsaid first means, a divider circuit connected to the output of saidtrigger circuit operable to add a count only when said trigger circuit.[.appears.]. .Iadd.operates .Iaddend.to a predetermined one of saidstates to provide a predetermined signal, a plurality of output circuitsfor said divider circuit, each of which output circuits provides a pulseoutput in response to an input of a different number of saidpredetermined signals by said trigger circuit, and selection means forselectively connecting a different one of said divider circuits to saiddata record circuit.
 10. A survey recorder as set forth in claim 9 inwhich said meter device includes a rotating disc which has a reflectivesurface and a nonreflective section on said surface and said pulsegenerator circuit comprises means for projecting a light in thedirection of said reflective surface, pickup means for providing a firstsignal output in response to the detection of light reflected from saidsurface and a second signal output responsive to interruption of thereflected light by said nonreflected section, and said trigger circuitis connected to the output of said pickup means and operative to a firststate in response to said first signal and operable to a second stateresponsive to said second signal.
 11. A survey recorder as set forth inclaim 9 in which said data record includes a control transistor which isoperative to complete a current path over the first record head windingin one direction in response to a first pulse output from said dividercircuit, and a current path over the first record head winding in anopposite direction in response to a second signal output from saiddivider circuit.
 12. In a survey recorder for recording data and timeinformation for use with a meter device having a rotating disc which hasa reflective surface and a nonreflective section on said surface, apulse initiator circuit comprising means for projecting a light in thedirection of said reflective surface, pickup means for providing a firstsignal output in response to the detection of light reflected from saidsurface and a second signal output responsive to interruption of thereflected light by said nonreflected section, a trigger circuitconnected to the output of said pickup means operative to a first statein response to said first signal and operable to a second stateresponsive to said second signal, a divider circuit connected to theoutput of said trigger circuit operable to add a count whenever saidtrigger circuit operates to a predetermined one of said states toprovide a predetermined signal, a plurality of output circuit for saiddivider circuit, each of which output circuits provides a pulse outputfor a different number of said predetermined signals input from saidtrigger circuit, a pulse recording circuit and selection means forselectively connecting a different one of said divider output circuitsto said pulse recording circuit.
 13. A survey recorder as set forth inclaim 12 in which said pulse output by said divider circuit at timescomprises a logic 1 signal and at other times comprises a logic 1 signaland at other times comprises a logic 0 signal, and which includes a datarecord circuit comprising a data record head and a switching devicewhich is operative in response to one of said pulses to effect theconduction of current over said data record head in a first direction,and operative in response to a different one of said pulses to effectcontrol of the current over said record head in the opposite direction.14. A survey recorder as set forth in claim 12 in which said rotatingdisc includes a plurality of nonreflection sections on said surface toprovide a correspondingly different pulse ratio output to said pulserecording circuit.
 15. In a survey recorder for recording data and timeinformation derived from an associated meter device, which surveyrecorder includes timer means operative to provide time referencesignals which represent predetermined intervals of time of operation ofsaid meter device, a time record circuit having a record head forrecording said time reference signals on a magnetic tape, a controlcircuit for said time record circuit including power sensor means fordetecting the presence of power and the interruption of power to saidmeter device for a predetermined time period, logic means connected tosaid power outage means and said timer means for controlling said timerecord circuit and said record head to record a discrete pulse format onsaid magnetic tape which identifies a detected power outage comprisingat least a first and a second half amplitude pulse of the same polarityrecorded in sequence on said tape, at least one of which occurssimultaneous with one of said time reference signals ouput from saidtimer means.
 16. A survey recorder as set forth in claim 15 in whichsaid logic means includes gate means connected to said timer means forproviding signals to control said time record circuit to at timesprovide current over said record head in a first direction, and to atother times control current flow over said record head in a seconddirection, a latch circuit operative to a first state with the detectionof poawer by said power sensor means for a given period, said latchcircuit being operative in said first state to provide output signals tosaid gate means to control said time record circuit to maintain zerolevel current to said record head from the time of the detection ofpower until a further time reference signal is provided to said logicmeans by said timer means.
 17. A survey recorder as set forth in claim16 which includes further means for operating said latch circuit to asecond state in response to said further time reference signal from saidtimer means, said latch circuit being operative to provide a signaloutput to said logic means in said second state which conditions saidgate means to control said time record circuit to reverse the directionof current flow in response to receipt thereafter of each time referencesignal from said timer means.
 18. In a survey recorder for recordingdata and time information derived from an associated meter device, whichsurvey recorder includes timer means operative to provide time referencesignals which represent predetermined intervals of time of operation ofsaid meter device, a time record circuit having a record head forrecording said time reference signals on a magnetic tape, a controlcircuit for said time record circuit including power sensor means fordetecting the presence of power and the interruption of power to saidmeter device for a predetermined time period, and logic means connectedto said power outage means and said timer means for controlling saidtime record circuit and said record head to record a discrete pulseformat on said magnetic tape which identifies a detected power outage..Iadd.
 19. A data recorder for recording metering information of ameasured quantity subject to an interruption during an outage condition,comprising: a data input for receiving pulses responsive topredetermined amounts of a measured quantity; a time impuse controlmeans actuated at regular time intervals; a switching control meanshaving one conductive condition in response to presence of said measuredquantity and an opposite conductive condition in response to the absenceof said measured quantity; a data recording circuit means connected tosaid data input to generate data recording pulses; a time recordingcircuit means including said time impulse control means to generate timeinterval recording pulses in response to each actuation of said timeimpulse control means; an outage indicating circuit means including saidswitching control means, said outage indicating circuit means beingconnected to said time recording circuit means to generate a separateoutage recording pulse in said time recording circuit in response tosaid switching control means being operated between said one and saidopposite conductive conditions such that said outage recording pulse isproduced in a predetermined relationship with respect to a time intervalpulse generated immediately after an outage condition in said measuredquantity. .Iaddend..Iadd.
 20. A data recorder for recording meteringinformation of a measured quantity subject to an interruption duringoutage conditions, comprising: a data input for receiving pulsesresponsive to predetermined amounts of a measured quantity; a timeimpulse control means actuated at regular time intervals; an outagedetector including a switching control means having one conductivecondition in response to presence of said measured quantity and oppositeconductive condition in response to the absence of said measuredquantity; a data recording circuit means connected to said data input togenerate data recording pulses; a time recording circuit means includingsaid time impulse control means; an outage indicating circuit meansincluding said switching control means, said outage indicating circuitmeans being connected to said time recording circuit means to generate aseparate outage pulse in said time recording circuit in response to saidswitching control means being operated between said one and saidopposite conductive conditions such that said outage pulse is producedin said time recording circuit means in a predetermined relationshipprior to a time interval pulse generated subsequent to an outagecondition in said measured quantity. .Iaddend..Iadd.
 21. In a recorderfor recording data and time information derived from an associated meterdevice, timer means, a time record circuit having a record headresponsive to said timer means for recording time reference signalsrepresenting predetermined intervals of time of operation of said meterdevice on a magnetic tape, and means responsive to said timer means andto interruption of power to said meter device for a predetermined timeperiod for controlling said time record circuit and record head torecord a discrete pulse format on the magnetic tape which identifies adetected power interruption of said predetermined time period..Iaddend..Iadd.
 22. The recorder of claim 21 wherein said discrete pulseformat comprises a transition characteristic of a detected powerinterruption in a predetermined relationship to a transition of the timereference signals. .Iaddend..Iadd.
 23. The recorder of claim 21 whereinsaid discrete pulse format comprises a transition characteristic of adetected power interruption in a predetermined time relationship to atransition of the time reference signals. .Iaddend..Iadd.
 24. Therecorder of claim 23 wherein said power interruption characteristictransition has an amplitude which is distinctly different from said timereference signal transition. .Iaddend. i .Iadd.25. In a recorder forrecording data and time information derived from an associated meterdevice, timer means, a time record circuit having a record head andresponsive to said timer means for recording time reference signals on amagnetic tape which represent predetermined intervals of time ofoperation of said meter device, and means for detecting the interruptionof power to the meter device for a predetermined time and producing asignal characteristic of the occurrence of such power interruption inresponse to operation of said timer means after the power has returnedto the meter device, said time record circuit being responsive to thecharacteristic signal to record a discrete pulse format on said magnetictape which identifies the detected power interruption. .Iaddend..Iadd.26. In a recorder for recording data and time information derived froman associated meter device, timer means, a time record circuit having arecord head and responsive to said timer means for recording said timereference signals on a magnetic tape which represent predeterminedintervals of time of operation of said meter device, and a controlcircuit for said time record circuit comprising means switchable to afirst state in response to interruption of power to the meter device fora predetermined time period, for switching from the first state thereofto a second state in response to said timer means after power isreturned to the meter device, said time record circuit being responsiveto said switching from the first to the second state to record adiscrete pulse format on the magnetic tape which identifies the detectedpower interruption. .Iaddend.